1. Field of the Invention
The present invention relates to methods of producing iron from iron ore, and more particularly, but not by way of limitation, to an improved method of producing iron and/or steel from iron ore wherein the iron ore is charged to a blast furnace along with coke and limestone and blasted with a heated reducing gas stream.
2. Description of the Prior Art
Blast furnaces have been utilized for many years in the steel industry for converting iron ore into molten pig iron. Generally, such blast furnaces are large shaft reactors wherein a continually descending column of iron ore, coke and limestone is blasted with a continuous stream of air preheated to a high temperature. In its descent through the shaft, the iron ore is reduced to molten iron by reaction with the ascending gas stream and by reaction with carbon in the furnace. Heretofore, the heated reducing gas stream has been generated by passing a stream of air through one or more regenerative stoves wherein the air is heated. Typically, the regenerative stoves are comprised of one or more large refractory lined towers and are operated by first heating the refractory by combustion of fuel and air therein and then forcing a stream of air through the tower so that it is heated. Such regenerative stoves or towers are generally expensive to install, difficult to operate and the refractory materials require expensive periodic maintenance.
By the present invention an improved method of producing iron and steel from iron ore is provided wherein regenerative stoves are not required and the preheated reducing gas stream is generated in relatively inexpensive easy-to-operate combustion apparatus.